Bombus bimaculatus Cresson, 1863

Bombus bimaculatus Cresson, 1863: 92 [♂].

     Holotype ♂. USA, Connecticut, by E. Norton [type lost].

Bombus Ridingsii Cresson, 1878: 182 [♀]. Synonymy by Franklin (1913: 305).

     Lectotype ♀, designated by Cresson (1916: 129), USA, West Virginia, by J. Ridings [ANSP no. 2635].

Bombus ridingsi Kirby, 1878: 130. Lapsus of Bombus ridingsii Cresson, 1878.

Bremus bimaculatus var. ahenus Bequaert and Plath, 1925: 275 [♀, ♂]. Synonymy by Krombein (1979: 2198).

     Holotype ♀ [queen]. USA, Massachusetts, Forest Hills, by O.E. Plath [MCZ no. 15281].

Bremus bimaculatus var. arboreti Bequaert and Plath, 1925: 276 [♀]. Synonymy by Krombein (1979: 2198).

     Holotype ♀ [queen]. USA, Massachusetts, Forest Hills, 2 June 1924, by O.E. Plath [MCZ no. 15282].

Taxonomic notes: Franklin (1913: 306) and Cresson (1916: 113) indicated that the male holotype for Bombus bimaculatus Cresson, 1863 was lost, though the former indicated that three additional males identifed by Cresson were also in the ANSP; one of these could serve as a neotype, as Frankin (1913: 306) felt that the male on which the original description was based was aberrant. Lovell (1907: 199) even felt that this species was likely a variety of B. vagans Smith, 1854, likely due to the variability in the extent of yellow on tergum 2.

The varieties described by Bequaert and Plath (1925) are also seemingly based on aberrant specimens of Bombus bimaculatus Cresson, 1863, each with slightly atypical colouration; var. ahenus was even reared from a colony of typical specimens (Bequaert and Plath 1925: 276).

Though Franklin (1913: 305) and Robertson (1929: 4) had previously recognized B. ridingsii Cresson, 1878 as the female of B. bimaculatus, Burks (1951: 1251) recognized all three of the latter names as varieties of B. bimaculatus.

DNA Barcode Index Number (BIN): BOLD:AAA8078

Distribution in Canada: Couper 1883 [Canada, as Bombus ridingsii Cresson]; Gibson 1914 [ON]; Pengelly 1953 [ON]; Mitchell 1962 [ON]; Judd 1966 [ON]; MacFarlane and Pengelley 1975 [ON]; Vander Kloet 1977 [NS?]; MacFarlane and Pengelley 1977 [ON]; Lavery and Harder 1988 [ON]; Richards et al. 2011 [ON]; Sheffield et al. 2014 [MB]; Williams et al. 2014 [MB, ON, QC]; Normandin et al. 2017 [QC]; Brooks and Nocera 2020 [NB]; Dominey 2021 [NS]; Sharkey 2022 [ON]; Gibbs et al. 2023 [MB]; Sheffield and Palmier 2023 [SK, MB, ON, QC, NB, PE, NS].

Though this species has been historically known from soutern Ontarion in Canada, Sheffield and Palmier (2023) provided evidence that its range has undergone recent and rapid spread into the Maritime and Prairie Provinces.